While it is widely accepted that fluoride exerts a cariostatic effect, the mechanism of this effect remains undefined. Further, it is unclear whether the fluoride in the oral fluids represents a significant source of fluoride for the enamel. Few of the variables which could conceivably influence the concentration of fluoride in the oral fluids have been studied and, indeed, the mechanisms of fluoride handling in certain of the oral fluids, namely the secretions of the minor salivary glands and the gingival fluid, have apparently received no study at all. The proposed studies are designed to identify those variables which can influence the rates of fluoride delivery by the various oral fluids and the fluoride concentrations of these fluids. These fluids include mixed, whole saliva, the secretions of the parotid, submandibular, sublingual, and minor salivary glands, as well as the gingival fluid. The variables include flow rate, time of day, plasma fluoride concentration, the acid-base status of the systemic extracellular fluids and intraoral fluids, and the concentrations of Na ion, K ion, Cl-, Mg ions, Ca ions, PO4-3, CO2, H ions, and HCO3-. Several acute and chronic experimental approaches will be employed including the clearance and perfused duct techniques. Results from these studies will provide a clearer understanding of the mechanisms of fluoride handling by salivary glands. Regional differences in the intraoral fluoride concentrations will be identified. In the long term, these results should contribute to an understanding of the cariostatic mechanism(s) of fluoride.